For many decades, inventors have studied and attempted to improve the lenticular stereogram, also known as the parallax panoramagram. The art has been very well traveled and is very well understood. By incorporating a cylindrical lenticular screen, corduroy-like, over the surface of a properly encoded print, a stereoscopic depth effect may be achieved. As shown in FIG. 1, the lenticules 102 have semi-cylindrical surfaces aligned so that their length is in the vertical direction. The lenticules are in intimate juxtaposition with a print surface 105, which contains columns of encoded visual information. Each column is associated with a particular lenticule, and within each column there will be found a series of views ranging from a leftmost to a rightmost perspective. Thus, the observer of a panoramagram print will see two perspectives rather than one due to the refractive surface of the panoramagram.
There are many prior art suggestions which are similar to the lenticular stereogram in their effect. These autostereoscopic displays have several features in common. For one thing, the selection device is in intimate juxtaposition with the display or print surface. For another, a large number of views is required, rather than just two views as is the case for a plano-stereoscopic display like the polarized light method for motion picture projection, or in the occlusion principle which is incorporated in the CrystalEyes® line of products manufactured by StereoGraphics Corporation.
It has been noted that the panoramagram depth content must be restricted because of the lack of sharpness as depth increases. Inventors have addressed this problem with various suggestions for making improvements. Indeed, in the case of a series of patents assigned to the Nimslo Corporation in the early 1980's, the essence of their art for a mass-consumer lenticular and camera print system is to provide a means for the operator to make an adjustment to place the most important part of the picture at the print surface, with zero parallax, so it would be sharp. It was understood at that time and even to this day, that only the subject which is at the plane of the display will be sharply in focus. Prior patents which discuss this problem and/or solutions include U.S. Pat. Nos. 3,960,563; 4,037,950; 4,063,265; 4,086,585; and 4,124,291.
Stereographers have accepted this limitation. Those working in the field have been able to mask the defect, because it can be made to appear to be identical to the loss of sharpness which occurs in normal photographic reproduction due to depth of field effects. Indeed, in a typical panoramagram having a distant background and powerful stereoscopic effects which reach above the plane of the display, there will be an attempt to mask the lack of sharpness by suggesting that loss of focus is attributable to depth of field. This is a limitation that those skilled in the art of creating such displays have gotten around because of their artistic skill. Yet it is clear that the major benefit of the parallax panoramagram is to offer depth content. As long as the depth content is compromised, the display cannot be considered to be a fully perfected visual medium.
The present invention sets out to vastly increase the sharpness of the parallax panoramagram, and do so with means that are inexpensive and which produce an unequivocal improvement in sharpness for objects both in the distance and apparently close to the observer.